See the picture for all detail, I have done it by hand. Few important steps; -Take the first derivative -Put it equal to zero -you get the x value which is equal to 11 -Now for the check that x=11 is the least value or not, take the second derivative -As, the 2nd derivative is positive so it is the least value
As x=0 in 1964 add 11 to it so at x=11 we get 1975 so in this year car have least value